Increase In Energy Production Research Articles

Structural Contradictions Between Energy Production and Consumption Along With Economic Development and Environmental Protection in China: Evidence and Policy Implications

This paper empirically describes and analyzes the structural contradictions between energy production and consumption in the Chinese local economy. Alongside rapid economic growth, energy usage in China increased gradually and exceeded energy production for a long time. For some particular energy sources such as petroleum, the gap between supply and demand is relatively larger than that of the whole energy sector in the economy. The process of turning fossil fuels into final energy products for use causes a great deal of pollution, especially emitting industrial waste gases, such as particulate matter emission, into the atmospheric environment. Increasing energy production directly and greatly to solve the gap between energy supply and demand in the economy may impact environmental quality and not meet sustainable development needs. It is difficult to coordinate energy production and consumption when considering economic development and environmental protection in economic operation. Importing energy could meet the excess energy consumption in a short period but often fluctuates from foreign energy market changes and global political events. For policy recommendations, some policies which directly lower energy consumption may impact economic development since industry is the main consumer of energy, and industrial production is an important component of GDP in China. Declining the role of the industry sector in the economy and reducing industrial product exports, including some energy-intensive products, could solve the structural contradictions between energy production and consumption under the condition of maintaining economic development and protecting the environment in China, but this is a long-term adjustment process.

Computational investigation into the effect of material properties on aeroacoustics based damage detection from wind turbine blades

A wind turbine blade monitoring system would provide significant benefit to wind farm owners and operators by reducing operation and maintenance costs and increasing energy production by limiting turbine downtime. Previous work has demonstrated potential success of a system based on monitoring the flow-generated sound with blade internal cavity microphones. In this study, the effect of blade material acoustic properties is investigated to provide recommendations on the potential application of this approach. A reduced-order model is used to identify the flow-generated lumped-parameter acoustic sources outside the blade at a frequency of 10 kHz. A feasible range of acoustic properties is used for the blade and shear web acoustic transmission coefficient and acoustic reflection coefficient. Damage detection success improved as reflection increased, as more sound propagated toward to the root of the blade. However, the damage detection success rate did not consistently increase with an increase or decrease in the transmission coefficient and balance must be achieved depending on the specific blade and the expected flow-generated sound. These results demonstrate the usefulness of quantifying the blade material acoustic properties and will be used to strategically design a blade monitoring system.

Ginsenoside Rf Enhances Exercise Endurance by Stimulating Myoblast Differentiation and Mitochondrial Biogenesis in C2C12 Myotubes and ICR Mice.

Ginsenoside Rf (G-Rf) is a saponin of the protopanaxatriol family and a bioactive component of Korean ginseng. Several ginsenosides are known to have a positive effect on exercise endurance, but there is not yet a report on that of G-Rf. Forced swimming tests were performed on G-Rf-treated mice to evaluate the effect of G-Rf on exercise endurance. Subsequently, the expression of markers related to myoblast differentiation and mitochondrial biogenesis in murine skeletal C2C12 myotubes and tibialis anterior muscle tissue was determined using Western blotting, quantitative real-time polymerase chain reaction, and immunofluorescence staining to elucidate the mechanism of action of G-Rf. The swimming duration of the experimental animal was increased by oral gavage administration of G-Rf. Moreover, G-Rf significantly upregulated the myoblast differentiation markers, mitochondrial biogenesis markers, and its upstream regulators. In particular, the mitochondrial biogenesis marker increased by G-Rf was decreased by each inhibitor of the upstream regulators. G-Rf enhances exercise endurance in mice, which may be mediated by myoblast differentiation and enhanced mitochondrial biogenesis through AMPK and p38 MAPK signaling pathways, suggesting that it increases energy production to satisfy additional needs of exercising muscle cells. Therefore, G-Rf is an active ingredient in Korean ginseng responsible for improving exercise performance.

Advanced technologies on the sustainable approaches for conversion of organic waste to valuable bioproducts: Emerging circular bioeconomy perspective

Rapid population growth and other human activities have generated massive waste from various sectors in recent decades. Studies revealed that by 2050, global solid waste generation is expected to reach 70% to 3.4 billion metric tons. Thus, the authorities urgently need to provide a low-cost, efficient technology for treating waste disposal. However, it is evident that only 20% of waste is recycled, and the remaining is still being considered for landfilling. In developing countries, the generated waste is simply disposed of in an open area, which causes a severe threat to humans, animals, and the environment. To date, organic waste and fourth-generation biomass have been investigated for multiple targeted products. Thus, the present review article highlights the emerging problems in organic waste generation, management, and converting them into various value-added bioproducts. This review also deals with the conversion of multiple biofuels such as liquid, solid, gaseous, and bioelectricity from organic waste resources. Besides, the latest approaches in organic waste are also detailly addressed for the production of value-added bioproducts such as bioplastic, bio-compost, and organic acids. Furthermore, the techno-economic analysis (TEA) and life cycle assessment (LCA) of organic waste is also explored. The transformation of organic waste to value-added bioproducts enhances the circular bioeconomy approach by reducing waste, increasing energy production, and other healthcare products. Finally, it is concluded that the utilization of organic waste to value-added bioproducts and biofuels production will be helpful in achieving high energy security, environmental protection, as well as enhancing the bioeconomy perspective.

Curtailment and acoustic deterrents reduce bat mortality at wind farms

AbstractThe impacts of wind energy on bat populations is a growing concern because wind turbine blades can strike and kill bats, and wind turbine development is increasing. We tested the effectiveness of 2 management actions at 2 wind‐energy facilities for reducing bat fatalities: curtailing turbine operation when wind speeds were <5.0 m/second and combining curtailment with an acoustic bat deterrent developed by NRG Systems. We measured the effectiveness of the management actions using differences in counts of bat carcasses quantified by daily and twice‐per‐week standardized carcass searches of cleared plots below turbines, and field trials that estimated searcher efficiency and carcass persistence. We studied turbines located at 2 adjacent wind‐energy facilities in northeast Illinois, USA, during fall migration (1 Aug–15 Oct) in 2018. We estimated the effectiveness of each management action using a generalized linear mixed‐effects model with several covariates. Curtailment alone reduced overall bat mortality by 42.5% but did not reduce silver‐haired bat (Lasionycteris noctivagans) mortality. Overall bat fatality rates were 66.9% lower at curtailed turbines with acoustic deterrents compared to turbines that operated at manufacturer cut‐in speed. Curtailment and the deterrent reduced bat mortality to varying degrees between species, ranging from 58.1% for eastern red bats (Lasiurus borealis) to 94.4 for big brown bats (Eptesicus fuscus). Hoary (Lasiurus cinereus) and silver‐haired bat mortality was reduced by 71.4% and 71.6%, respectively. Our study lacked a deterrent‐only treatment group because of the expense of acoustic deterrents. We estimated the additional reduction in mortality with concurrent deployment of the acoustic deterrent and curtailment under the assumption that curtailment and the acoustic deterrent would have reduced mortality by the same percentage at adjacent wind‐energy facilities. Acoustic deterrents resulted in 31.6%, 17.4%, and 66.7% additional reductions of bat mortality compared to curtailment alone for eastern red bat, hoary bat, and silver‐haired bat, respectively. The effectiveness of acoustic deterrents for reducing bat mortality at turbines with rotor‐swept area diameters >110 m is unknown because high frequency sound attenuates quickly, which reduces coverage of rotor‐swept areas. Management actions should consider species differences in the ability of curtailment and deterrents to reduce bat mortality and increase energy production.

An urban-scale method for building roofs available wind resource evaluation based on aerodynamic parameters of urban sublayer surfaces

• A convenient urban-scale wind resource assessment method was proposed. • A moving grid was proposed to calculate the aerodynamic parameters. • The potential of low-rise buildings in urban areas using wind energy was revealed. • A criterion to assess the wind energy above urban building roofs was developed. For the limited areas of building rooftops, installing wind turbines can increase energy production, as compared to paving over the photovoltaic panels, and can serve as a viable means for complementary power generation. However, a concise criterion for estimating the availability of wind energy in the built environment is lacking. In this work, the aerodynamic parameters method was integrated with a moving grid of a semicircle with a radius of 500 m to develop an urban-scale wind energy evaluation model. The wind energy utilisation potential of buildings’ rooftops in a given city (in this case, Hangzhou) was estimated. The results show that a certain portion of low-rise buildings has considerable available wind resources. By statistical analysis of the millions of calculated results, two criteria for rooftop's wind resources assessment have been developed. Compared with the buildings in a previously planned region having small spacing and low average height characteristics, the buildings of the newly planned region were spacious, resulting in its suitability for wind energy utilisation proportion being 10.2% higher. Besides, the proportion of residential buildings that are suitable for wind use is higher than that of public buildings and industrial buildings, for the average height difference.

Super-rated operational concept for increased wind turbine power with energy storage

• New method of Region 3 operation proposed to increase power production. • Hydraulic transmission and energy storage proposed to decouple rotor and generator. • Super-rated operation has the potential to increase energy production by 23% • Capacity factor may increase from 53% to 66% without increasing generator size. • This system will require solving several hydraulic transmission engineering issues. A new super-rated method of wind turbine control is proposed for operation between rated and cut-out wind speeds, in conjunction with integrated energy storage, that may allow dramatically increased power capture as well as improved energy dispatchability without increasing turbine size or generator size. In the proposed system, a hydraulic transmission is used to decouple the wind turbine rotor from the electric generator, allowing for mechanical energy storage to be integrated into the system before the generator. Rather than the conventional Region 3 control, the new super-rated Region 3 + operation allows the rotor to generate additional power above the rated power limit and store that additional power for later regeneration. In this Region 3+ operation, the limit on operation is based on rotor thrust loads (instead of rotor power) so that power can increase with increasing wind speed. A case study with the NREL 5 MW reference turbine in steady Class I winds showed that super-rated operation could increase annual power production by 23% (including hydraulic transmission storage losses), without increasing mean out-of-plane blade loads, rotor size, or generator power. In addition, this new operation for this case increases the capacity factor from 53% to 66%, which increases power levelization. However, a wide array of component design issues must be addressed (especially for the hydraulic drivetrain) to determine if this potential can be realized.

PSIII-9 Effects of Dietary Carnitine Supplementation on Semen Output and Quality in Boars

Abstract Carnitine is an amino acid derivative with functions in increasing energy production as well as acting as an antioxidant for sperm cells. The objective of this study is to investigate the effects of the inclusion of carnitine in boar diets on sperm output and quality. Sixty-four boars at a commercial boar stud were blocked by age and semen quality and randomly allotted to receive a daily 30 g top-dress of either corn (CON) or corn and 625 mg of carnitine (CARN). Supplementation lasted for 12 weeks from May-July, 2021 during which weekly semen collection was performed. Semen was evaluated at the stud for concentration and motility parameters using computer-assisted semen analysis (CASA). Samples were also shipped to Purdue University for detailed morphology, viability, and CASA performed in samples stored at 17C for 5 d. PROC Mixed (SAS v 9.4) was used to evaluate the data where boar nested within treatment was used in repeated measures with the main effects of treatment and week and semen quality estimates from the week prior to supplementation as covariates in the model. Carnitine supplementation had no effects on total sperm produced (P = 0.35). Percentage of motile sperm cells (P = 0.38), morphologically normal sperm (P=0.42), viable sperm (P = 0.43), or sperm with normal acrosomes (P = 0.61) in the ejaculates was not different among treatments. Sperm kinematics in CARN ejaculates tended to have greater straight-line velocity and distance (P = 0.06 and P = 0.07, respectively). There were several interactions of treatment and day of storage for the kinematic parameters, however, these interactions do not show an observable trend for CARN to improve or depress sperm function. Overall, the inclusion of 625 mg/d of carnitine to the diet for 12 weeks had no effects on sperm output or quality with minor changes to sperm cell kinematics.

Unearthing the alleviatory mechanisms of hydrogen sulfide in aluminum toxicity in rice

Hydrogen sulfide (H2S) improves aluminum (Al) resistance in rice, however, the underlying mechanism remains unclear. In the present study, treatment with 30-μM Al significantly inhibited rice root growth and increased the total Al content, apoplastic and cytoplasm Al concentration in the rice roots. However, pretreatment with NaHS (H2S donor) reversed these negative effects. Pretreatment with NaHS significantly increased energy production under Al toxicity conditions, such as by increasing the content of ATP and nonstructural carbohydrates. In addition, NaHS stimulated the AsA-GSH cycle to decrease the peroxidation damage induced by Al toxicity. Pretreatment with NaHS significantly inhibited ethylene emissions in the rice and then inhibited pectin synthesis and increased the pectin methylation degree to reduce cell wall Al deposition. The phytohormones indole-3-acetic and brassinolide were also involved in the alleviation of Al toxicity by H2S. The transcriptome results further confirmed that H2S alleviates Al toxicity by increasing the pathways relating to material and energy metabolism, redox reactions, cell wall components, and signal transduction. These findings improve our understanding of how H2S affects rice responses to Al toxicity, which will facilitate further studies on crop safety.

Polydatin Attenuates Intra-Uterine Growth Retardation-Induced Liver Injury and Mitochondrial Dysfunction in Weanling Piglets by Improving Energy Metabolism and Redox Balance.

The present study investigated the potential of polydatin to protect against liver injury and the mitochondrial dysfunction of weanling piglets suffering from intra-uterine growth retardation (IUGR). Thirty-six normal birth weight weanling piglets and an equal number of IUGR littermates were given a basal diet with or without polydatin (250 mg/kg) from 21 to 35 d of age. Plasma and liver samples were collected to measure biochemistry parameters at 35 d of age. IUGR caused hepatic apoptosis, mitochondrial dysfunction, and oxidative damage, along with a lower efficiency of energy metabolism and inferior antioxidant ability. Polydatin decreased apoptotic rate, improved the features of mitochondrial damage, inhibited mitochondrial swelling and superoxide anion formation, and preserved mitochondrial membrane potential in the liver. Concurrently, polydatin promoted mitochondrial biogenesis, increased sirtuin 1 activity, and upregulated the expression levels of several genes related to mitochondrial function and fitness. Polydatin also facilitated mitochondrial oxidative metabolism with a beneficial outcome of increased energy production. Furthermore, polydatin mitigated the IUGR-induced reduction in manganese superoxide dismutase activity and prevented the excessive accumulation of oxidative damaging products in the liver. These findings indicate that polydatin confers protection against hepatic injury and mitochondrial dysfunction in the IUGR piglets by improving energy metabolism and redox balance.

On optimal energy-extraction performance of arrays of wave-energy converters, with full consideration of wave and multi-body interactions

An array of ocean-wave energy converters, compared to a stand-alone device, provides lower energy-production costs but affects the aggregate power performance. Previous studies suggested that wave-interaction effects within the array could increase energy production by over 15% per device. However, no physical constraints on the WECs were considered in these studies; as a result, the devices can experience unrealistically large motions. A control strategy is thus desirable to coordinate individual WECs and maximize the energy extraction. We apply model-predictive control (MPC) to an array of point-absorber-type WECs by developing a formulation that accommodates hard constraints on the motion of each device and on the Power-takeoff (PTO) forces with excellent computational efficiency. Full multi-body wave-interaction effects are computed by a semi-analytical method within linear-wave theory. This framework enables us to demonstrate results of realistic maximal power production for arrays of two, three, and four devices operating under constraints in sea waves of various incident angles. It is observed that wave–body interactions have actually destructive effects on the array power production for the majority cases in irregular sea waves. Also discussed are effects of the reactive power produced by the PTO unit and the possibility of removing it within the MPC framework.

Weakened resilience of benthic microbial communities in the face of climate change

Increased ocean temperature associated with climate change is especially intensified in coastal areas and its influence on microbial communities and biogeochemical cycling is poorly understood. In this study, we sampled a Baltic Sea bay that has undergone 50 years of warmer temperatures similar to RCP5-8.5 predictions due to cooling water release from a nuclear power plant. The system demonstrated reduced oxygen concentrations, decreased anaerobic electron acceptors, and higher rates of sulfate reduction. Chemical analyses, 16S rRNA gene amplicons, and RNA transcripts all supported sediment anaerobic reactions occurring closer to the sediment-water interface. This resulted in higher microbial diversities and raised sulfate reduction and methanogenesis transcripts, also supporting increased production of toxic sulfide and the greenhouse gas methane closer to the sediment surface, with possible release to oxygen deficient waters. RNA transcripts supported prolonged periods of cyanobacterial bloom that may result in increased climate change related coastal anoxia. Finally, while metatranscriptomics suggested increased energy production in the heated bay, a large number of stress transcripts indicated the communities had not adapted to the increased temperature and had weakened resilience. The results point to a potential feedback loop, whereby increased temperatures may amplify negative effects at the base of coastal biochemical cycling.

A review on graphene / graphene oxide supported electrodes for microbial fuel cell applications: Challenges and prospects

Microbial Fuel Cell (MFC) has gained great interest as an alternative green technology for bioenergy generation along with reduced sludge production, nutrient recovery, removal of COD and color, etc. during wastewater treatment. However, the MFC has several challenges for real-time applications due to less power output and high ohmic resistance and fabrication (electrode and membrane) cost. Several kinds of research have been carried out to increase energy production by reducing various losses associated with electrodes in the MFC. Though, carbonaceous electrodes (carbon and graphite) are the key materials for the anode and cathode side, since these have a higher surface area, good biocompatibility, low cost, and good mechanical strength. Graphene or graphene oxide-based nanocomposite can be an ideal substitute for electrode modifications and an alternative for an expensive anode and cathode catalyst in MFC. Graphene oxide synthesis from waste material such as waste biomass, agricultural, plastic waste, etc. is added advantages of minimizing the cost of the electrodes. But, the synthesis of graphene is quite expensive and has limitations in economic feasibility for bioelectricity production in MFC. Hence, the present review deals with the anode and cathode electrode modification with graphene-based nanocomposites, synthesis of graphene/graphene oxide from various raw materials, and its application in MFC. The current challenges and future outlook on graphene-based composites on MFC performance are also discussed.

Optimal closed-loop wake steering – Part 2: Diurnal cycle atmospheric boundary layer conditions

Abstract. The magnitude of wake interactions between individual wind turbines depends on the atmospheric stability. We investigate strategies for wake loss mitigation through the use of closed-loop wake steering using large eddy simulations of the diurnal cycle, in which variations in the surface heat flux in time modify the atmospheric stability, wind speed and direction, shear, turbulence, and other atmospheric boundary layer (ABL) flow features. The closed-loop wake steering control methodology developed in Part 1 (Howland et al., 2020c, https://doi.org/10.5194/wes-5-1315-2020) is implemented in an example eight turbine wind farm in large eddy simulations of the diurnal cycle. The optimal yaw misalignment set points depend on the wind direction, which varies in time during the diurnal cycle. To improve the application of wake steering control in transient ABL conditions with an evolving mean flow state, we develop a regression-based wind direction forecast method. We compare the closed-loop wake steering control methodology to baseline yaw-aligned control and open-loop lookup table control for various selections of the yaw misalignment set-point update frequency, which dictates the balance between wind direction tracking and yaw activity. In our diurnal cycle simulations of a representative wind farm geometry, closed-loop wake steering with set-point optimization under uncertainty results in higher collective energy production than both baseline yaw-aligned control and open-loop lookup table control. The increase in energy production for the simulated wind farm design for closed- and open-loop wake steering control, compared to baseline yaw-aligned control, is 4.0 %–4.1 % and 3.4 %–3.8 %, respectively, with the range indicating variations in the energy increase results depending on the set-point update frequency. The primary energy increases through wake steering occur during stable ABL conditions in our present diurnal cycle simulations. Open-loop lookup table control decreases energy production in the example wind farm in the convective ABL conditions simulated, compared to baseline yaw-aligned control, while closed-loop control increases energy production in the convective conditions simulated.

PV Rooftop Repowering Potential In Indonesia: Study Case

Indonesia is intensively building solar energy, which divided into three types, namely rooftop, solar farm, and floating solar with a target-installed capacity of 37.15 GW. A lot of land area is required for the development of solar energy for the next 20-25 years. The average land area required for 1 PV module is approximately 2 m2, so it is predicted that the new land area needed will be difficult to obtain in the future. Repowering is a solution to deal with these potential problems, repowering is an interesting new business in Europe when we have to face power plants that have entered the end-of-life. The study aims to analyze if repowering is implemented, we can reduce the Levelized Cost of Electricity. A plant with a capacity of 1.4 MWp will be used as the basis for the simulation. Using a monitoring system to see energy production, temperature, irradiance, and performance ratio is used as the methodology for collecting data. After that, it will analyze from a technical and economic point of view. The result shows that energy production increased by 24% or by 10,645,786 kWh and the Levelized Cost of Electricity decreased by 0.02 USD/kWh with an IRR of 5.67% and a payback period of 14.5 years. This study finds that repowering can reduce electricity tariffs and increase energy production.

Identifying effective operating rules for large hydro–solar–wind hybrid systems based on an implicit stochastic optimization framework

Optimization of operational strategies of a hydro–solar–wind hybrid renewable energy system (HRES) could increase resource use efficiency without additional investment. However, because of the myopic nature of the short-term forecast information, the short-term optimal operation strategy of the large HRES cannot guarantee a satisfactory long-term system performance. Therefore, it is necessary to explore reasonable long-term operation strategies for the hydro–solar–wind HRES, especially the establishment of operating rules. In this study, we proposed a method to identify effective long-term operating rules for the large hydro–solar–wind HRES based on an implicit stochastic optimization framework. A large hydro–solar–wind HRES located in the upper Yellow River, China was selected as a case study. It was found that: (1) Operating rules taking reservoir storage or water level as the output variable and available energy as the input variable were most effective to guide the complementary operation of the hydro–solar–wind HRES; (2) Compared with a standard operating policy, the identified best operating rules could increase energy production and guaranteed rate of the HRES by 5.2% and 4%, respectively; and (3) Complementary management of hydro, solar and wind could increase the energy production of the hydropower system, when power transmission capacity was large enough.

Modeling the effect of disaggregated renewable energies on ecological footprint in E5 economies: Do economic growth and R&D matter?

In recent decades, environmental degradation due to economic activities has become a severe concern for policymakers. Therefore, emerging economies do not exclude from this issue. The analysis about determinants of environmental degradation has become an increasing research direction, but researchers have not yet answered clearly. The present study provides novel empirical analysis to fill this gap by considering the impact of production-side disaggregated renewable energies with growth and R&D expenditure on ecological footprint. This study adopts the panel dynamic Generalized Method of Moments (GMM) alongside Fully Modified Ordinary Least Square (FMOLS) to estimate the long-term association among selected variables in selected five emerging economies over the period of 1990 to 2019. The empirical result shows a positive and significant impact of economic growth on environmental degradation (ED). Subsequently, the outcomes indicate that increasing production of geothermal and hydro energy causes to rise in ED. Moreover, it finds that increasing energy production by nuclear and wind sources reduced the ED. Such outcomes are fascinating when energies have different behavior with ED due to some hurdles, i.e., its cost and R&D. Additionally, this study finds that expenditures on R& D have a positive and significant impact on the ecological footprint in selected economies as a 1% rise in R&D expenditures declines the environment quality by 0.075% and 0.082%. The estimated results also provide important policy implications for the selected and the other emerging economies in designing an appropriate way forward to a sustainable environment.

Multi-objective techno-economic generation expansion planning to increase the penetration of distributed generation resources based on demand response algorithms

Generation expansion planning in the power system is of particular importance. In traditional systems, investment in the generation expansion was made by the electricity company, but with the restructuring in the electricity industry, the owners of different parts of the system submit their proposals to the independent system operator and the independent system operator chooses the optimal design. Slowly increasing energy production from renewable sources can pose challenges for the grid. Increasing the penetration of renewable resources due to uncertainty in their production can reduce network reliability and thus increase system costs. The investigation on generation expansion planning is a multifaceted issue (technical and economic) that has been analyzed in various aspects in recent years. In this study, a multidimensional structure of generation expansion planning based on increasing the penetration level of distributed generation resources (renewable and non-renewable) as well as the application of load management and demand response algorithms is proposed. The proposed model is scheduled based on two levels of primary and secondary development. In the primary, the development of generation and transmission based on large-scale power plants as well as solar and wind farms are presented. In the secondary, in order to reduce the power fluctuations caused by the distributed generation’s units, non-stochastic power generation units such as micro turbines, gas turbines and combined heat and power have been utilized. To overcome the difficulties in solving the problem of hybrid and non-convergent mixed-integer problem, the adaptive particle swarm optimization has been hired. The simulation results indicate that in the second scenario, where the development of the generation expansion planning is based on the integration of distributed generation resources and power plants, it is more cost-effective. In addition to, these simulation results represent the accuracy of the proposed probabilistic method in planning of dynamic generation systems in order to estimate the probability density function and the optimal output variables in multi-objective techno-economic planning.

Robust Heat Shock Response in Chlamydia Lacking a Typical Heat Shock Sigma Factor.

Cells reprogram their transcriptome in response to stress, such as heat shock. In free-living bacteria, the transcriptomic reprogramming is mediated by increased DNA-binding activity of heat shock sigma factors and activation of genes normally repressed by heat-induced transcription factors. In this study, we performed transcriptomic analyses to investigate heat shock response in the obligate intracellular bacterium Chlamydia trachomatis, whose genome encodes only three sigma factors and a single heat-induced transcription factor. Nearly one-third of C. trachomatis genes showed statistically significant (≥1.5-fold) expression changes 30 min after shifting from 37 to 45°C. Notably, chromosomal genes encoding chaperones, energy metabolism enzymes, type III secretion proteins, as well as most plasmid-encoded genes, were differentially upregulated. In contrast, genes with functions in protein synthesis were disproportionately downregulated. These findings suggest that facilitating protein folding, increasing energy production, manipulating host activities, upregulating plasmid-encoded gene expression, and decreasing general protein synthesis helps facilitate C. trachomatis survival under stress. In addition to relieving negative regulation by the heat-inducible transcriptional repressor HrcA, heat shock upregulated the chlamydial primary sigma factor σ66 and an alternative sigma factor σ28. Interestingly, we show for the first time that heat shock downregulates the other alternative sigma factor σ54 in a bacterium. Downregulation of σ54 was accompanied by increased expression of the σ54 RNA polymerase activator AtoC, thus suggesting a unique regulatory mechanism for reestablishing normal expression of select σ54 target genes. Taken together, our findings reveal that C. trachomatis utilizes multiple novel survival strategies to cope with environmental stress and even to replicate. Future strategies that can specifically target and disrupt Chlamydia’s heat shock response will likely be of therapeutic value.

Energy as a substitute for factors of production: case study of an oil rich economy

ABSTRACT Academic literature and policy notes place great emphasis on the relationship between energy carriers and factors of production. We have evidence from a subsidized economy that provides nationwide energy subsidies; with inferences that partly contradict previous findings. We use a panel of Iranian plants from 2004 to 2013. In 2010, the country conducted an energy reform to increase energy productivity. We use translog functions with SUR and GMM estimators, with clustered and robust standard errors. As a result, the elasticity of energy carriers for labor wages is positive, showing that energy is a substitute for labor on average. The substitution pattern of labor is weakened in parallel with the country's 2010 reform, but not lost completely. Regarding capital, a worsening financial accessibility to the economy after UN sanctions hit the economy in 2012 seemed to have an adverse effect on capital and energy relations.